1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef _LIBCPP___ALGORITHM_COPY_H
10 #define _LIBCPP___ALGORITHM_COPY_H
11 
12 #include <__algorithm/copy_move_common.h>
13 #include <__algorithm/iterator_operations.h>
14 #include <__algorithm/min.h>
15 #include <__config>
16 #include <__iterator/segmented_iterator.h>
17 #include <__type_traits/common_type.h>
18 #include <__utility/move.h>
19 #include <__utility/pair.h>
20 
21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22 #  pragma GCC system_header
23 #endif
24 
25 _LIBCPP_PUSH_MACROS
26 #include <__undef_macros>
27 
28 _LIBCPP_BEGIN_NAMESPACE_STD
29 
30 template <class, class _InIter, class _Sent, class _OutIter>
31 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter> __copy(_InIter, _Sent, _OutIter);
32 
33 template <class _AlgPolicy>
34 struct __copy_loop {
35   template <class _InIter, class _Sent, class _OutIter>
36   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
37   operator()(_InIter __first, _Sent __last, _OutIter __result) const {
38     while (__first != __last) {
39       *__result = *__first;
40       ++__first;
41       ++__result;
42     }
43 
44     return std::make_pair(std::move(__first), std::move(__result));
45   }
46 
47   template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
48   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
49   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
50     using _Traits = __segmented_iterator_traits<_InIter>;
51     auto __sfirst = _Traits::__segment(__first);
52     auto __slast  = _Traits::__segment(__last);
53     if (__sfirst == __slast) {
54       auto __iters = std::__copy<_AlgPolicy>(_Traits::__local(__first), _Traits::__local(__last), std::move(__result));
55       return std::make_pair(__last, std::move(__iters.second));
56     }
57 
58     __result = std::__copy<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__sfirst), std::move(__result)).second;
59     ++__sfirst;
60     while (__sfirst != __slast) {
61       __result =
62           std::__copy<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__end(__sfirst), std::move(__result)).second;
63       ++__sfirst;
64     }
65     __result =
66         std::__copy<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__local(__last), std::move(__result)).second;
67     return std::make_pair(__last, std::move(__result));
68   }
69 
70   template <class _InIter,
71             class _OutIter,
72             __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
73                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
74                           int> = 0>
75   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
76   operator()(_InIter __first, _InIter __last, _OutIter __result) {
77     using _Traits = __segmented_iterator_traits<_OutIter>;
78     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
79 
80     if (__first == __last)
81       return std::make_pair(std::move(__first), std::move(__result));
82 
83     auto __local_first      = _Traits::__local(__result);
84     auto __segment_iterator = _Traits::__segment(__result);
85     while (true) {
86       auto __local_last = _Traits::__end(__segment_iterator);
87       auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
88       auto __iters      = std::__copy<_AlgPolicy>(__first, __first + __size, __local_first);
89       __first           = std::move(__iters.first);
90 
91       if (__first == __last)
92         return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
93 
94       __local_first = _Traits::__begin(++__segment_iterator);
95     }
96   }
97 };
98 
99 struct __copy_trivial {
100   // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
101   template <class _In, class _Out,
102             __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
103   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
104   operator()(_In* __first, _In* __last, _Out* __result) const {
105     return std::__copy_trivial_impl(__first, __last, __result);
106   }
107 };
108 
109 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
110 pair<_InIter, _OutIter> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
111 __copy(_InIter __first, _Sent __last, _OutIter __result) {
112   return std::__dispatch_copy_or_move<_AlgPolicy, __copy_loop<_AlgPolicy>, __copy_trivial>(
113       std::move(__first), std::move(__last), std::move(__result));
114 }
115 
116 template <class _InputIterator, class _OutputIterator>
117 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
118 copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
119   return std::__copy<_ClassicAlgPolicy>(__first, __last, __result).second;
120 }
121 
122 _LIBCPP_END_NAMESPACE_STD
123 
124 _LIBCPP_POP_MACROS
125 
126 #endif // _LIBCPP___ALGORITHM_COPY_H
127